Spiral 1 and Spiral 2 are two video art programs by Dick Ainsworth, co-writer of the Bally BASIC instruction manual. These programs are written for the Bally Arcade game system, more commonly called by its 1981 re-release name of Astrocade. Both programs are included in the 1978 original Bally BASIC manual and its 1981 "AstroBASIC" re-release. The video art is created using a few program loops and LINE command statements to fill the screen with a random, semi-controlled, pattern.
Spiral 1 appears in the appendix of programs at the back of both BASIC manuals (page 103 of the Bally BASIC manual and on page 75 of the "AstroBASIC" manual). Spiral 2 is built-up from smaller BASIC pieces in Chapter 8: Video Art (pages 93-96 of the Bally BASIC manual pages 62-64 of the "AstroBASIC" manual). The chapter explains how the program works.
This video overview is broken into various sections:
0:00 - Spiral 1 and 2 - Titles and Overview 19:44 - Spiral 2, Loads and Runs 22:53 - Spiral 2, "AstroBASIC" Program Listing 23:12 - Spiral 1, Loads and Runs 26:26 - Spiral 1, "AstroBASIC" Program Listing 26:42 - End Credits
The eight-page Video Art chapter in the Bally BASIC manual gives users new to programming a chance to try their newly acquired skills to create art. Spiral 1 and Spiral 2, simple programs that could be easily modified, inspired many Bally Arcade users. Judging from the printed content of the two main Astrocade newsletters (Arcadian and Cursor/BASIC Express), video games and video art became the two most popular ways that amateur programmers on the Astrocade platforms used their systems. Perhaps without the video art chapter and these two simple BASIC example programs, there would not have been as much video art created on the Bally system. That would have been a shame, as the art that clever programmers created on the Astrocade platform over the next seven to eight years is quite impressive given the limited 1.8KB of RAM and 160x88 resolution of the console.